1. Field of the Invention
The invention relates to a display panel, and more particularly, to a transflective liquid crystal display panel.
2. Description of the Prior Art
According to the source of illuminating light, liquid crystal displays can be divided into three categories, such as transmissive, reflective, and transflective modes. The transmissive liquid crystal display has a backlight for producing light. The light produced by the backlight will pass through the liquid crystal panel to allow users to see the image displayed on the display panel. The reflective liquid crystal display has a reflective electrode. When displaying an image, the ambient light of the reflective liquid crystal display will enter the liquid crystal display from the observer side of the user and then be reflected by the reflective electrode. The reflected light will pass through the liquid crystal panel again and the resulting image will be shown on the display panel. The transflective liquid crystal display has both transmissive mode and reflective mode. In other words, each pixel area of the transflective liquid crystal display includes a transmitting region and a reflecting region, in which the transmitting region of the display uses backlight as a light source and the reflecting region of the display uses ambient light as a light source.
Please refer to FIG. 1. FIG. 1 illustrates a perspective view of a transflective liquid crystal display according to the prior art. As shown in FIG. 1, the conventional transflective liquid crystal display 36 includes a display panel 10 and a backlight module 34. The display panel 10 includes a top substrate 12, a bottom substrate 14, and a liquid crystal layer 16 disposed between the top substrate 12 and the bottom substrate 14. Additionally, the display panel 10 includes a plurality of pixels 18 disposed between the top substrate 12 and the bottom substrate 14, in which each of the pixels 18 includes a transmitting region 20 and a reflecting region 22. Preferably, the transmitting region 20 includes a transparent pixel electrode 24 formed on the bottom substrate 14 and the reflecting region 22 includes a reflecting electrode 26 disposed on the bottom substrate 14 surrounding the transparent pixel electrode 24.
The display panel 10 also includes a color filter 28 formed on the surface of the top substrate 12 and a transparent conductive layer 30 disposed on the color filter 28. The color filter 28 includes regions of different colors, such as red, green, and blue regions. Alternatively, the color filter 28 can be formed on the bottom substrate 14 to form a color filter on array (COA) substrate. The operation of the transflective liquid crystal display 36 involves a transmissive mode and a reflective mode. Under the operation of the transmissive mode, light generated by the backlight module 34 would pass from the bottom substrate 14, the transparent pixel electrode 24, the liquid crystal layer 16, the color filter 28, and exit via the top substrate 12. Under the operation of the reflective mode, ambient light would pass from the top substrate 12 and the color filter 28 to the reflecting electrode 26. After being reflected by the reflecting electrode 26, light would pass through the color filter 28 again and exit via the top substrate 12.
The pixel 18 of the display panel 10 is disposed between the top substrate 12 and the bottom substrate 14, and the color filter 28 is disposed on the surface of the top substrate 12. With reference to FIG. 2, FIG. 2 illustrates a pixel of the transflective liquid crystal display panel according to the prior art. As shown in FIG. 2, the pixel 18 of the display panel 10 includes a plurality of subpixels 31, 32, and 33 disposed between the top substrate 12 and the bottom substrate 14, in which each of the subpixels is disposed with respect to a color of the color filter 28. For instance, the subpixel 31 is disposed corresponding to the red region of the color filter 28, the subpixel 32 is disposed corresponding to the green region of the color filter 28, and the subpixel 33 is disposed corresponding to the blue region of the color filter 28.
It should be noted that in the conventional liquid crystal display, the region between subpixels with respect to either the transmitting region or the reflecting region does not include any transparent conductive electrode thereon. As a result, the liquid crystals in this region are aligned unevenly during a dark state, which ultimately causes light leakage and contrast degradation. In order to prevent this problem, the fabrication of recent transflective liquid crystal displays utilizes black matrices 35 to block these regions that are prone to light leakage. However, in the present design of utilizing black matrices, the width of the overlapped portion of the black matrices 35 of the transmitting region 20 is equal to that of the reflecting region 22. This design facilitates the blocking of light leaked from the transmitting region but also degrades the aperture ratio of the reflecting region.